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【新文速递】2024年7月12日固体力学SCI期刊最新文章

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今日更新:International Journal of Solids and Structures 2 篇,Journal of the Mechanics and Physics of Solids 1 篇,Mechanics of Materials 1 篇,Thin-Walled Structures 4 篇

International Journal of Solids and Structures

Serendipitous relationship between discrete distribution models representing random orientations of fillers in composite materials and the golden ratio

Hiroyuki Ono

doi:10.1016/j.ijsolstr.2024.112962

表示复合材料中填料随机方向的离散分布模型与黄金比例之间的偶然性关系

The purpose of this study is to establish simple discrete distribution models capable of expressing the two and three-dimensional random orientation states of fillers in composite materials. Initially, a new method is proposed to divide the elastic constants into isotropic and anisotropic parts. Employing this method, for the composite material containing ellipsoidal fillers with various orientations in the material, the macroscopic elastic constants and thermal expansion coefficients of the material are derived based on the Mori–Tanaka method. Subsequently, the analysis of the macroscopic properties is performed for fillers oriented two and three-dimensional discrete distributions. As a result, it is found that when both angular pitches of the azimuth angle and the rotational angle of the fillers in a plane are at most 72°, the macroscopic elastic constants and the thermal expansion coefficients of the material exhibit in-plane isotropy, leading to the realization of a two-dimensional random state. Furthermore, if the angular distribution of the zenith angle and azimuth angle corresponds to the vertices of the regular dodecahedron and icosahedron, and the angular pitch of the rotational angle of the fillers is at most 72°, the macroscopic properties of the material become isotropic, resulting in a three-dimensional random state. Notably, the angle of 72° and the orientation angles of the vertices of the regular dodecahedron and icosahedron are associated with the golden ratio. Therefore, this analysis suggests a serendipitous relationship between the golden ratio and the angular pitch that simplifies the random orientation distribution of fillers.

本研究的目的是建立能够表达复合材料中填料的二维和三维随机取向状态的简单离散分布模型。首先,提出了一种将弹性常数分为各向同性和各向异性两部分的新方法。利用这种方法,对于材料中含有不同取向的椭圆形填料的复合材料,根据 Mori-Tanaka 方法推导出材料的宏观弹性常数和热膨胀系数。随后,对取向为二维和三维离散分布的填料进行了宏观特性分析。结果发现,当填料在一个平面上的方位角和旋转角的角度间距均不超过 72°时,材料的宏观弹性常数和热膨胀系数表现出平面内各向同性,从而实现二维随机状态。此外,如果天顶角和方位角的角度分布与正十二面体和二十面体的顶点相对应,且填料旋转角的角间距最大为 72°,则材料的宏观特性会变得各向同性,从而实现三维随机状态。值得注意的是,正十二面体和二十面体顶点的 72°角和取向角与黄金分割率有关。因此,这一分析表明,黄金分割率与角间距之间存在偶然关系,可简化填料的随机取向分布。


A contact model for the functionally graded coated elastic structures: Extension of the Hertz theory to the contact of beam structures

Chenxi Wei, Yin Zhang

doi:10.1016/j.ijsolstr.2024.112968

功能梯度涂覆弹性结构的接触模型:赫兹理论在梁结构接触中的推广

The Hertzian displacement assumption is widely used in analyzing the contact problems of non-uniform elastic bodies. It is essential to account for the support conditions of the elastic body as they significantly influence the contact stiffness and distribution of contact pressure. To address this, the deformation of beam structures is integrated into the Hertzian displacement assumption, which leads to the development of an extended contact mechanics model suitable for the elastic bodies of a beam structure which can be non-uniform and with functionally graded coatings. The problem is solved by using a numerical method based on the Gauss-Chebyshev quadrature for the singular integral equation of Cauchy type. In the contact problems of the doubly simply supported (SS-SS) and cantilever beams, the contact pressure and contact stiffness in conjunction with the interactions between the indentation and contact bodies are discussed. An in-depth study on the coupling effects between the structural deformation and functionally graded coatings is presented.

赫兹位移假设被广泛用于分析非均匀弹性体的接触问题。考虑弹性体的支承条件对接触刚度和接触压力的分布有重要影响。为了解决这个问题,梁结构的变形被整合到赫兹位移假设中,从而导致了适用于非均匀和具有功能梯度涂层的梁结构弹性体的扩展接触力学模型的发展。采用基于高斯-切比雪夫正交的数值方法求解柯西型奇异积分方程。在双简支梁与悬臂梁的接触问题中,讨论了接触压力和接触刚度以及压痕与接触体之间的相互作用。对结构变形与功能梯度涂层之间的耦合效应进行了深入的研究。


Journal of the Mechanics and Physics of Solids

Effects of nonlinearities and geometric imperfections on multistability and deformation localization in wrinkling films on planar substrates

Jan Zavodnik, Miha Brojan

doi:10.1016/j.jmps.2024.105774

非线性和几何缺陷对平面基底起皱膜多稳定性和变形局部化的影响

Compressed elastic films on soft substrates release part of their strain energy by wrinkling, which represents a loss of symmetry, characterized by a pitchfork bifurcation. Its development is well understood at the onset of supercritical bifurcation, but not beyond, or in the case of subcritical bifurcation. This is mainly due to nonlinearities and the extreme imperfection sensitivity. In both types of bifurcations, the energy–displacement diagrams that can characterize an energy landscape are non-convex, which is notoriously difficult to determine numerically or experimentally, let alone analytically. To gain an elementary understanding of such potential energy landscapes, we take a thin beam theory suitable for analyzing large displacements under small strains and significantly reduce its complexity by reformulating it in terms of the tangent rotation angle. This enables a comprehensive analytical and numerical analysis of wrinkling elastic films on planar substrates, which are effective stiffening and/or softening due to either geometric or material nonlinearities. We also validate our findings experimentally. We explicitly show how effective stiffening nonlinear behavior (e.g., due to substrate or membrane deformations) leads to a supercritical post-bifurcation response, makes the energy landscape non-convex through energy barriers causing multistability, which is extremely problematic for numerical computation. Moreover, this type of nonlinearity promotes uni-modal, uniformly distributed, periodic deformation patterns. In contrast, nonlinear effective softening behavior leads to subcritical post-bifurcation behavior, similarly divides the energy landscape by energy barriers and conversely promotes localization of deformations. With our theoretical model we can thus explain an experimentally observed phenomenon that in structures with effective softening followed by an effective stiffening behavior, the symmetry is initially broken by localizing the deformation and later restored by forming periodic, distributed deformation patterns as the load is increased. Finally, we show that initial imperfections can significantly alter the local or global energy-minimizing deformation pattern and completely remove some energy barriers. We envision that this knowledge can be extrapolated and exploited to convexify extremely divergent energy landscapes of more sophisticated systems, such as wrinkling compressed films on curved substrates (e.g., on cylinders and spheres) and that it will enable elementary analysis and the development of specialized numerical tools.

软基材上的压缩弹性薄膜通过起皱释放部分应变能,这代表了对称性的丧失,其特征是干草叉分叉。它的发展很好地理解在超临界分岔的开始,但不是超越,或在亚临界分岔的情况下。这主要是由于非线性和极端不完美的灵敏度。在这两种类型的分岔中,可以表征能量格局的能量位移图都是非凸的,这是众所周知的难以通过数值或实验确定的,更不用说分析了。为了对这种势能景观有一个初步的了解,我们采用了一种适合分析小应变下大位移的细梁理论,并通过将其重新表述为切线旋转角来显著降低其复杂性。这使得能够对平面基底上的起皱弹性薄膜进行全面的分析和数值分析,这些薄膜由于几何或材料非线性而有效地硬化和/或软化。我们还通过实验验证了我们的发现。我们明确地展示了有效的强化非线性行为(例如,由于衬底或膜变形)如何导致超临界分岔后响应,使能量景观通过能量垒引起的多稳定性而非凸,这对于数值计算来说是非常有问题的。此外,这种类型的非线性促进单模态,均匀分布,周期性变形模式。相反,非线性有效软化行为导致亚临界后分叉行为,同样通过能量势垒划分能量景观,反过来促进变形的局部化。通过我们的理论模型,我们可以解释一种实验观察到的现象,即在具有有效软化随后具有有效硬化行为的结构中,对称性最初通过局部变形被打破,随后通过形成周期性分布的变形模式随着载荷的增加而恢复。最后,我们发现初始缺陷可以显著改变局部或全局能量最小化变形模式,并完全消除一些能量障碍。我们设想,这些知识可以外推和利用,以凸化更复杂系统的极端发散的能量景观,如弯曲基片上的褶皱压缩膜(例如,在圆柱体和球体上),它将使基本分析和专门的数值工具的发展成为可能。


Mechanics of Materials

Probabilistic progressive damage modeling of hybrid composites

E. Polyzos, I.A. Rodrigues Lopes, P.P. Camanho, D. Van Hemelrijck, L. Pyl

doi:10.1016/j.mechmat.2024.105087

混杂复合材料的概率渐进损伤模型

A novel analytical probabilistic progressive damage model (PPDM) is introduced for multiphase composites to predict the damage behavior of hybrid composites. The PPDM is based on effective field methods and the stochastic nature of fiber damage is captured by including weakest link theory and Weibull statistics. Three additional models are developed to compare with the PPDM. A stochastic model analogous to the PPDM (called SPDM), and two finite element models, one stochastic (SFEM) and one probabilistic (PFEM). All models are developed in a thermodynamically consistent framework and are extended to include residual thermal stresses. Finally, the four models are compared with models from the open literature for an AS4-M50S hybrid carbon–carbon composite with different hybridization ratios of high to low elongation fibers. The comparison reveals a great agreement between all models and indicates that the stochastic nature of fiber damage is the most influential parameter leading to damage.

为预测复合材料的损伤行为,提出了一种新的多相复合材料的概率渐进损伤分析模型。该方法基于有效场方法,通过引入最弱环节理论和威布尔统计来捕捉纤维损伤的随机性。另外还开发了三个模型与PPDM进行比较。一个类似于PPDM的随机模型(称为SPDM),以及两个有限元模型,一个随机(SFEM)和一个概率(PFEM)。所有模型都是在热力学一致的框架中开发的,并扩展到包括残余热应力。最后,将这四种模型与公开文献中具有不同高低伸长纤维杂化比的AS4-M50S杂化碳-碳复合材料模型进行了比较。结果表明,纤维损伤的随机性是影响纤维损伤的最主要参数。


Thin-Walled Structures

A scale-span method to characterize the mechanical property of BCF/PEEK considering uncertain structural characteristics

Yong Liu, Qiannan Li, Meng Zhu, Pan Sun, Honggen Zhou

doi:10.1016/j.tws.2024.112211

考虑不确定结构特性的BCF/PEEK力学性能标度跨度表征方法

The focus of this study is exploring a scale-span characterization method to predict the mechanical properties of Braided Carbon Fiber Reinforced Poly Ether Ether Ketone (BCF/PEEK) considering structural uncertainty. Firstly, a complicated micro-scale representative volume element (RVE) model that considers the random position and size of fiber was established via the developed Python script. Analogously, a mathematical expression adopted by the trust region algorithm was proposed to accurately describe the detailed cross-sectional shapes and fluctuation amplitude characteristics of BCF/PEEK for the sake of establishing the precision meso-scale RVE model. Then, the corresponding elastic properties that consider fiber volume fraction and fiber distribution location were characterized via the span-scale characterization method. Meanwhile, the influence of fiber bundle fluctuation amplitude and fiber volume fraction on the mechanical properties was investigated as well. In addition, the mechanical properties of BCF/PEEK with the change of the braid angle between warp and weft yarn were predicted via the established meso-scale RVE model. Finally, a series of experiments have been carried out. The maximum and minimum absolute prediction deviation of all elastic property parameters were only 4.07% and 1.41%, respectively, which verified the proposed scale-span characterization method can predict the mechanical properties of composites well.

本研究的重点是探索一种考虑结构不确定性的尺度跨度表征方法来预测编织碳纤维增强聚醚醚酮(BCF/PEEK)的力学性能。首先,通过开发的Python脚本,建立了考虑纤维位置和尺寸随机的复杂微尺度代表性体积元(RVE)模型;同样,为了建立精确的中尺度RVE模型,提出了信赖域算法所采用的数学表达式来准确描述BCF/PEEK的详细截面形状和波动幅度特征。然后,通过跨尺度表征方法对考虑纤维体积分数和纤维分布位置的弹性性能进行表征。同时,研究了纤维束波动幅度和纤维体积分数对复合材料力学性能的影响。此外,通过建立的中尺度RVE模型,预测了BCF/PEEK的力学性能随经纬纱编织角度的变化。最后,进行了一系列的实验。各弹性性能参数的绝对预测偏差最大值和最小值分别为4.07%和1.41%,验证了所提出的尺度跨度表征方法能够较好地预测复合材料的力学性能。


Interactive buckling behaviour of Q420–Q960 steel welded thin-walled H-section long column

Jie Wang, Jin Di, Yuanlin Zheng, Fengjiang Qin, Yi Su

doi:10.1016/j.tws.2024.112219

Q420-Q960型钢焊接薄壁h型长柱的相互作用屈曲行为

Considering the broad application prospect of high-strength steel (HSS) in engineering structure, and the limitations present in existing studies on interactive buckling of HSS welded thin-walled box-section long column, both test and finite element analysis were employed to investigate the interactive buckling behaviour exhibited by 12 specimens fabricated from Q420–Q960 steels. The detailed analysis considered various aspects, including the failure mode, axial deformation, interaction of local and overall buckling deformation, and the ultimate bearing capacity. Observations revealed that the utilization rate of steel strength diminished with an escalation in both the plate width–thickness ratio and steel strength. An increase in the plate width–thickness ratio correlated with an earlier onset of local buckling, and the influence of steel strength was found to be negligible. More importantly, the limit of the plate width–thickness ratio for columns undergoing interactive buckling increased with a rise in column slenderness and decreased with an increase in steel strength. Taking into account the influence of column slenderness and steel strength, a novel calculation formula for determining the limit of the plate width–thickness ratio was derived. It is noteworthy that Eurocode 3 and JGJ/T 483-2020 were found too conservative for calculating the ultimate bearing capacity, while ANSI/AISC 360-22 was found suitable. Additionally, a calculation method for the ultimate bearing capacity of Q420–Q960 steel welded thin-walled H-section long column was proposed based on the direct strength method.

考虑到高强钢在工程结构中的广阔应用前景,以及现有高强钢焊接薄壁箱形截面长柱相互屈曲研究的局限性,采用试验和有限元分析相结合的方法,对q420 ~ q960钢制作的12个试件的相互屈曲行为进行了研究。详细分析考虑了破坏模式、轴向变形、局部和整体屈曲变形的相互作用以及极限承载力等多个方面。观察发现,钢强度利用率随板宽厚比和钢强度的增加而降低。板宽厚比的增加与局部屈曲的早期发生相关,并且发现钢强度的影响可以忽略不计。更重要的是,相互屈曲柱的板宽厚比极限随柱长细比的增大而增大,随钢强度的增大而减小。考虑柱长细比和钢强度的影响,导出了确定板宽厚比极限的新计算公式。值得注意的是,对于极限承载力的计算,欧洲规范3和JGJ/T 483-2020过于保守,而ANSI/AISC 360-22较为合适。此外,提出了基于直接强度法的Q420-Q960型钢焊接薄壁h型钢长柱极限承载力计算方法。


Vibration behaviours of composite conical–cylindrical shells with damping coating: Theory and experiment

Jinan Li, Hui Li, Yao Yang, Yanhong Fang, Haijun Wang, Xiangping Wang, Haiyang Zhang, Haizhou Wang, Hang Cao, Junxue Hou, Guowei Sun, Dongxu Du, Xiaofeng Liu, Zhuo Xu, Wei Sun, Zhong Luo, Qingkai Han

doi:10.1016/j.tws.2024.112218

有阻尼涂层的锥形圆柱复合壳的振动特性:理论与实验

This study presents the theoretical and experimental investigations on vibration behaviours of carbon fiber/ resin composite conical-cylindrical shells (or C-C shells) with damping coating. First, an analytical model of such a combined shell with coating material considers the effects of base harmonic excitation load under arbitrary boundary conditions is proposed using the first-order shear deformation theory, virtual artificial spring technique, modal superposition approach, the Rayleigh-Ritz method, etc. Subsequently, the solutions of fundamental frequencies, mode shapes, and vibration displacements in the frequency domain are acquired by deriving the corresponding energy expressions and motion equations. Convergence analysis is utilized to determine the virtual spring stiffness value and the appropriate truncation numbers. Both literature and experimental results are conducted to give an adequate validation of the current model, in which the continuous 3D printing technology is adapted to fabricate two C-C shell specimens with one of the outside surfaces being sprayed by coating material using an atomization deposition approach. Finally, the effects of the coating thickness ratio, Young's modulus ratio of the coating and the substrate shell, the semi-vertex angle, and the fiber laying angle on the free vibration and forced vibrations of the coated structure are discussed, with some practical recommendations being provided to improve the vibration suppression of such a coated structure.

本文对碳纤维/树脂复合材料锥形圆柱壳(或C-C壳)的阻尼特性进行了理论和实验研究。首先,利用一阶剪切变形理论、虚拟人工弹簧技术、模态叠加法、瑞利-里兹法等方法,建立了考虑任意边界条件下基谐激励载荷影响的复合壳体与涂层材料的解析模型;然后,通过推导相应的能量表达式和运动方程,得到基频、模态振型和振动位移在频域的解。利用收敛分析确定虚拟弹簧刚度值和适当的截断数。通过文献和实验结果对现有模型进行了充分的验证,采用连续3D打印技术制备了两个C-C壳体样品,其中一个外表面采用雾化沉积方法喷涂涂层材料。最后,讨论了涂层厚度比、涂层与基壳的杨氏模量比、半顶角和纤维铺设角对涂层结构自由振动和强迫振动的影响,并提出了一些实用的建议,以改善涂层结构的抑振性能。


Effect of solid blocking on lateral bracing requirements for cold-formed steel wall studs

Linbo Zhang, Lei Xu, Ronald D. Ziemian, Constance Ziemian

doi:10.1016/j.tws.2024.112208

固体阻塞对冷弯型钢壁钉横向支撑要求的影响

The effectiveness of horizontal bracing in increasing the strength of cold-formed steel (CFS) load-bearing walls has been widely acknowledged. However, while significant research has been conducted regarding the bracing requirements for CFS bearing walls, the effect of solid blocking, which prevents columns (studs) within the wall from rotating, has not been fully explored. In this study, we propose an analytical method to quantitatively assess the effect of solid blocking on bracing requirements for CFS load-bearing walls. This method is comprehensive as it can be applied to systems with different bracing patterns, load patterns, or non-identical columns (studs), and it accounts for the columns’ initial curvature and semi-rigid end connections. It has been verified that considering the solid blocking always decrease the bracing requirements because the existence of solid blocking increases the system’s stiffness and subsequently decreases the additional displacement as well as the brace force, as expected. An example consisting of 23 CFS studs is presented to illustrate how the effect of solid blocking on bracing requirements is influenced by the location and interval of solid blocking, the stiffness of column end connections, and the characteristics of tie bracing. The results indicate that the effect of solid blocking on bracing requirements increases when the location of solid blocking is closer to the anchor and the solid blocking interval is smaller. Moreover, a modification to the equation in AISI S100 is proposed to account for the effect of solid blocking on the strength requirement of tie bracing. Overall, this research contributes to a better understanding of the role of solid blocking in CFS load-bearing walls and provides insights for optimizing bracing design in practice.

水平支撑在提高冷弯型钢承重墙强度方面的有效性已得到广泛认可。然而,尽管已经对CFS承重墙的支撑要求进行了大量研究,但尚未充分探索阻止墙内柱(螺柱)旋转的固体阻塞的影响。在这项研究中,我们提出了一种分析方法来定量评估固体阻塞对CFS承重墙支撑要求的影响。该方法是全面的,因为它可以应用于具有不同支撑模式,负载模式或非相同柱(螺柱)的系统,并且它考虑了柱的初始曲率和半刚性端连接。研究结果表明,考虑实体堵塞总是降低支撑要求,因为实体堵塞的存在增加了系统的刚度,从而降低了附加位移和支撑力。以23根CFS螺栓为例,分析了固堵位置、固堵间距、柱端连接刚度和拉杆支撑特性对固堵对支撑要求的影响。结果表明:固堵位置越靠近锚杆,固堵间隔越小,固堵对支撑要求的影响越大;此外,还对AISI S100中的方程进行了修正,以考虑固体堵塞对拉杆支撑强度要求的影响。总的来说,本研究有助于更好地理解固体阻塞在CFS承重墙中的作用,并为实践中优化支撑设计提供见解。



来源:复合材料力学仿真Composites FEM
ACTMechanicalFluentSystemDeform振动复合材料非线性焊接理论材料试验螺栓
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首次发布时间:2024-11-21
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【新文速递】2024年7月14日固体力学SCI期刊最新文章

今日更新:Journal of the Mechanics and Physics of Solids 1 篇,Mechanics of Materials 1 篇,Thin-Walled Structures 1 篇Journal of the Mechanics and Physics of SolidsInteractions among phase transition, heat transfer and austenite plasticity in cyclic compression of NiTi shape memory alloys: Effect of loading frequencyKuo Zhang, Mingpeng Li, Qingping Sun, Lingyun Zhang, Guoan Zhoudoi:10.1016/j.jmps.2024.105782加载频率对NiTi形状记忆合金循环压缩相变、传热和奥氏体塑性的影响Displacement-controlled cyclic compressive responses of polycrystalline superelastic NiTi shape memory alloys (SMAs) are investigated at a maximum strain εmax of 4.2% and over frequencies ranging from 0.0007 Hz to 50 Hz in stagnant air. Our focus was on understanding the interactions among phase transition (PT), heat transfer and plastic flow of austenite phase during cyclic operation. We monitored temperature oscillations along with stress-strain relations and observed a critical frequency fcriAY, below which the responses were primarily influenced by the frequency-dependent coupling between PT and heat transfer, and above which macroscopic plastic deformation of the austenite phase played an important role in the cycling process, interacting with PT and heat transfer. The interactions at high frequencies (f>fcriAY) led to reductions in temperature magnitude, transition strain, latent heat, and hysteresis heat in subsequent cycles, eventually stabilizing the responses without plastic deformation. Theoretical analysis considering the interactions among PT, heat transfer, and plastic deformation was conducted to interpret and quantify the experimental findings. We find that the initiation and saturation of macroscopic plastic deformation of SMAs due to heat accumulation acted as a negative feedback mechanism in the cyclic responses, preventing the materials from overheating and potential damage in applications.研究了多晶超弹性镍钛形状记忆合金(SMA)在最大应变εmax 为 4.2%、频率范围为 0.0007 Hz 至 50 Hz 的停滞空气中的位移控制循环压缩响应。我们的重点是了解循环运行期间奥氏体相变 (PT)、传热和塑性流动之间的相互作用。我们监测了温度振荡和应力应变关系,并观察到一个临界频率 fcriAY,低于该频率时,响应主要受 PT 和热传递之间随频率变化的耦合影响,高于该频率时,奥氏体相的宏观塑性变形在循环过程中发挥重要作用,并与 PT 和热传递相互作用。高频率(f>fcriAY)下的相互作用导致后续循环中温度幅度、过渡应变、潜热和滞后热的降低,最终稳定了无塑性变形的响应。为了解释和量化实验结果,我们进行了理论分析,考虑了 PT、传热和塑性变形之间的相互作用。我们发现,热量积累导致的 SMA 宏观塑性变形的启动和饱和在循环响应中起到了负反馈机制的作用,防止了材料在应用中过热和潜在的损坏。Mechanics of MaterialsPrediction of viscoelastic effective creep compliances in cracked cross-ply composite laminatesKeiji Ogi, Shuji Yoshikawa, Tomonaga Okabe, Sota Onoderadoi:10.1016/j.mechmat.2024.105085 裂纹交叉铺层复合材料层合板的粘弹性有效蠕变柔度预测Viscoelastic effective creep compliances were predicted for symmetric composite laminates with constant matrix crack density. Following previous analytical models, the governing equations were solved in the Laplace domain, and the resulting displacement field was inverse Laplace transformed to obtain the displacement field, damage variables, and strain response to a given stress in the time domain. For the displacement field, both a series solution and a non-series solution were obtained. The non-series solution was then used to calculate the strain response of a cross-ply laminate subjected to constant stress under constant matrix crack density via the numerical inverse Laplace transform. To validate the model, the creep strains predicted using the model were compared with a finite element analysis solution, experimental results, and a synergistic damage mechanics solution.对具有恒定基体裂纹密度的对称复合材料层合板的粘弹性有效蠕变柔度进行了预测。在之前的分析模型基础上,对控制方程进行拉普拉斯域求解,对得到的位移场进行拉普拉斯逆变换,得到给定应力下的位移场、损伤变量和应变响应。对于位移场,得到了级数解和非级数解。然后利用非级数解,通过数值拉普拉斯逆变换计算了恒应力作用下恒矩阵裂纹密度下交叉铺层板的应变响应。为了验证模型的有效性,将模型预测的蠕变应变与有限元分析解、实验结果和协同损伤力学解进行了比较。Thin-Walled StructuresDigital twin-based non-destructive testing method for ultimate load-carrying capacity predictionLei Huang, Ziyu Xu, Tianhe Gao, Xiongwei Liu, Qingjie Bi, Bo Wang, Kuo Tiandoi:10.1016/j.tws.2024.112223基于数字孪生的极限承载能力预测无损检测方法Load-carrying experiments are essential for validating the mechanical performance of structural designs. Unpredictable early structure collapses during experiments would lead to severe safety accidents, and thus the real-time prediction of the ultimate load-carrying capacity (ULC) becomes highly necessary. However, due to multi-source experiment deviations, ULC prediction methods based on finite element (FE) analysis struggle to meet the high-accuracy and real-time requirements. To address this issue, this paper proposes a digital twin-based non-destructive testing (DT-NDT) method for ULC prediction. The method employs a deep neural network (DNN) to construct an experiment digital twin (DT) model in the offline phase. In the online phase, the experiment DT model utilizes the current measured strains to predict the ULC at future time steps in real-time, thus achieving non-destructive testing (NDT). First, a series of virtual experiments considering multi-source experiment deviations are carried out by FE analysis to obtain the virtual experiment dataset. The dataset includes strains and collapse loads corresponding to different experiment deviations and is augmented using the data augmentation approach based on structural symmetry. Subsequently, DNN is trained by the virtual experiment dataset to establish the mapping of strain values to collapse load. Finally, the strains are measured in real-time using strain gauges and the strain values are inputted into the DNN, i.e., the experiment DT model, to predict the collapse load. In this paper, the principle and effectiveness of the proposed method are illustrated through an analytical example and two experiment examples. In the experiment examples, the average relative errors of the DT-NDT method are 0.9% for an open-hole plate and -1.45% for a grid-stiffened cylindrical shell. The results illustrate the high prediction accuracy and effectiveness of the DT-NDT method, demonstrating its immense potential in NDT.承载试验是验证结构设计力学性能的必要条件。在试验过程中,不可预测的早期结构倒塌将导致严重的安全事故,因此对极限承载能力(ULC)的实时预测变得非常必要。然而,由于多源实验偏差,基于有限元(FE)分析的ULC预测方法难以满足高精度和实时性的要求。为了解决这一问题,本文提出了一种基于数字孪生的ULC无损检测(DT-NDT)方法。该方法采用深度神经网络(DNN)在离线阶段构建实验数字孪生(DT)模型。在在线阶段,实验DT模型利用当前测量的应变实时预测未来时间步长的ULC,从而实现无损检测(NDT)。首先,通过有限元分析,考虑多源实验偏差,进行一系列虚拟实验,得到虚拟实验数据集;该数据集包含不同实验偏差对应的应变和倒塌荷载,并采用基于结构对称性的数据增强方法进行扩充。随后,利用虚拟实验数据集对DNN进行训练,建立应变值与崩溃载荷的映射关系。最后,利用应变片实时测量应变,并将应变值输入DNN即实验DT模型,预测倒塌荷载。本文通过一个分析算例和两个实验算例说明了该方法的原理和有效性。在实验算例中,DT-NDT方法对开孔板的平均相对误差为0.9%,对网格加筋圆柱壳的平均相对误差为-1.45%。结果表明,DT-NDT方法具有较高的预测精度和有效性,显示了其在无损检测领域的巨大潜力。来源:复合材料力学仿真Composites FEM

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